The Skin Analysis and Epidermal Engineering Core was developed to enhance the productivity of all projects within this P01 by facilitating access and providing expertise in several important areas. The core will render state-of-the art embedding, sectioning (frozen or paraffin-embedded), routine staining, immunostaining, and creation of LRCs using retroviral constructs, in a timely and cost-efficient manner. Not only will conventional immunomarkers be available, but cutting-edge techniques with higher sensitivities and pathway specific immunoprobes aimed at defining: apoptosis markers, signal transduction pathways, and proliferation/differentiation pathways will also be used. All of the work performed in this core will be conducted by an experienced team with a track record of excellence and productivity. Cooperative interaction amongst members of this core and the projects will likely occur on a daily basis. Since Dr. Nickoloff has served as the Core Director for other relevant cores in the past such as the Immunopathology Core at the University of Michigan and the SCID Mouse Core at Loyola University, this expertise coupled with ongoing highly translational joint research efforts between Chicago and Ann Arbor will ensure the success of this core. The services will include the following: 1. To provide specialized handling of skin biopsy specimens derived from both human and murine tissues including cryopreservation and formalin fixation. 2. To provide routine staining (hematoxylin and eosin), as well as immunohistochemical staining of cryopreserved and paraffin embedded sections. 3. To provide expert dermatopathological reports of all stained sections with quantitative and semiquantitative measurements on all morphological analyses. 4. To prepare well-characterized retroviral constructs for transduction into epidermal equivalents (EEs) and Loyola raft cultures (LRCs) that will be utilized for in-vitro studies and skin graft experiments.